This invention relates generally to rolling mills, and is concerned in particular with an improved means for moving the combination of two vertical rolls and their respective upper and lower bearing chocks into and out of a roll housing.
In a rolling mill, periodic roll changes are required when the roll grooves become worn. In the past, various devices have been developed to assist operating personnel in making these changes, but for a variety of reasons, these devices have not proven entirely satisfactory. For example, none of the known prior art devices is capable of remaining attached to the bearing chocks during the rolling operation. Thus, valuable production time is lost during each roll change due to the fact that these roll changing devices must first be attached to the bearing chocks of the worn rolls prior to removing them from the housing, and further due to the fact that thereafter, these devices must be removed from the bearing chocks of the replacement rolls following their insertion into the roll housing. Mill down time is further lengthened in some cases because some of the prior art roll changing devices only operate on single rolls, thus doubling the time required to change each roll pair. Another drawback with many known roll changing devices lies in the fact that they are incapable of maintaining the work rolls in proper horizontal and vertical alignment during transfer from one location to another. This complicates the job of maintenance personnel, particularly at the stage when the replacement rolls are being inserted into the housing. With certain of the known roll changing devices, it is also possible for the roll cylinders to become demaged by banging against one another during transist to and from the roll housing. Still another known roll changing devices are not adjustable to accomodate different-sized rolls.
One object of the present invention is the provision of an improved roll changing device which can be employed to handle simultaneously two vertical rolls and their respective upper and lower bearing chocks, and which can remain attached to the upper bearing chocks during operation of the mill. This makes possible significant reductions in mill down time.
Another object of the present invention is the provision of a roll changing device which is readily adjustable to accommodate different-sized rolls.
Still another object of the present invention is the provision of a roll changing device which has the capability of maintaining the work rolls in proper horizontal and vertical alignment during transit, and of preventing the roll cylinders from coming into damaging contact with each other.